$ git clone -n https://src.fedoraproject.org/rpms/rubygem-gdk3.git /var/lib/mock/f42-build-side-1-3499993-45966/root/chroot_tmpdir/scmroot/rubygem-gdk3
Cloning into '/var/lib/mock/f42-build-side-1-3499993-45966/root/chroot_tmpdir/scmroot/rubygem-gdk3'...
$ git fetch origin 0559a6677b60f836bee884db1bcf24f6c972cb47:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-gdk3
 * [new ref]         0559a6677b60f836bee884db1bcf24f6c972cb47 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 0559a66 4.2.9 entry